Connective tissue such as ligaments and tendons can tear and detach from the bone and muscle to cause pain and disability. One such tissue is the acetabular labrum in the shoulder which, if torn from its associated bone or muscle, will cause pain and inability to elevate and rotate the arm. Complete separation of the tissue from the bone or muscle can occur if the body is subjected to gross trauma, but the separation can also start from a small lesion on the tissue, the bone or muscle due to aging and other factors.
A detached connective tissue can surgically be reattached to the bone and muscle by an “open” procedure that involves making an incision into the body and reconnecting tissue to the bone and muscle. In one such procedure, the muscle is completely detached from the tissue and bone and the bone is debrided to match the edge of tissue at the tissue/bone reattachment location. The bone is also abraded or notched at the reattachment location to expedite healing. To reattach the tissue to the bone, a series of small diameter holes referred to as transosseous tunnels are punched through the bone over a distance of about 2 cm to 3 cm on the bone. One end of the suture is attached to the muscle and the other end is attached to the bone by threading the suture through the transosseous tunnels and tying the suture to intact bone between two successive tunnels; thereafter, the incision is closed.
As used herein the portion of the suture attached to the tissue or bone is referred to as the “standing end”; the end that extends towards the handler, or is manipulated by the handler, is referred to as the “working end”; the distal end of the implant or suture is that portion located away from the handler; and the proximal end is located next to or near the handler.
As will be appreciated, because the open procedure detaches the muscle and abrades the bone, the patient may experience discomfort and a relatively long recovery time.
In an alternative procedure that reduces trauma to the patient, the reattachment is done arthroscopically. In an arthroscopic procedure the surgeon reconnects the tissue to the bone by working through a small trocar portal into the body to reattach the tissue. In one arthroscopic procedure, rather than using transosseous tunnels to thread the suture through the bone, which is difficult to achieve arthroscopically, the tissue is connected to the bone by attaching one end of the suture to the tissue, securing the other end of the suture in a bone anchor, and embedding the anchor in the bone at the appropriate location thereby reattaching the tissue to the bone.
Although arthroscopic procedures are less invasive than open procedures, an arthroscopic procedure is not always the procedure used. One reason is that arthroscopic suturing of the tissue requires a high level of skill not possessed by all surgeons. Also, arthroscopic suturing of the tissue is clumsy and time consuming and only the simplest stitch patterns can be utilized. Additionally, tying a suture knot arthroscopically is challenging because it is difficult to judge the tightness of the suture. Also, the tension on the suture is not easily adjustable arthroscopically once the knot is formed. Further, in arthroscopic suturing, the knot required to tie the tissue may end up on top of the tissue in the form of a knot bundle, which is undesirable because of the potential for postoperative irritation when the muscle is exercised.
U.S. patent application Ser. No. 10/942,275 by Fallin et al. (“Fallin”) discloses a line lock threading system useable for selectively adjusting and/or tying off a line using a line lock. The system includes a cartridge that includes a retention feature shaped to retain the line lock. The line lock comprises a body that bounds a plurality of passageways through which the line is treaded. The system also includes a treading feature shaped to facilitate insertion of the line through the passageways of the line lock.
U.S. Pat. No. 6,652,561 to Tran (“Tran”) assigned to the present applicant and hereby incorporated by reference herein for all purposes discloses an embeddable bone anchor that eliminates the need to tie a knot on the tissue, while allowing for adjusting the tension on the suture and the tissue. The suture is threaded through holes in the anchor such that on pulling on the suture, the suture and tissue are locked to the anchor without a knot on the tissue. A deployable structure on the anchor embeds the anchor body in the bone and resist pullout.
Co-pending U.S. patent application Ser. No. 11/375,691 by Forester et. al (“Forester et. al”), assigned to the present applicant and incorporated herein by reference for all purposes, discloses a suture lock and bone anchor that cinches the suture and tissue to the anchor without a knot on the tissue. As is illustrated in FIGS. 1 and 2 herein, a suture loop (12) is formed on the anchor (10) by fastening a first leg (12a) of the suture onto the distal end of the anchor, and threading the tail (16) of the suture through a plurality of holes (14a, 14b, 14c) in the anchor to form a second suture leg (12b) on the anchor. On pulling on the tail or working end of the suture (16), the suture tightens on the anchor to cinch the loop (12) and tissue (18) to the anchor, without a knot on the tissue. When the anchor (10) is embedded in the bone (20) the fixed leg (12a), which is the standing end of the suture, is positioned distally on the anchor. Barbs (24) on the anchor assist in embedding the anchor and resisting pullout from the bone.
In procedures for reconnecting tissue to bone using anchors, there is a continuing need for systems to improve the threading of sutures to the anchors, and which avoid tying knots on the tissue. It is therefore and objective of the present invention to address these needs.